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    <title>Document</title>
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<body>
    <h2>定义变量</h2>
</body>
<script>
    const count = 10;
    var a = 10;
    var a = 20;
    const b = 20;
    // b = 120;
    const obj = {
        name: 'alice',
        age: 20
    }

    obj = 999

    obj.name = 'jack'
    console.log('002count:', obj)
</script>

</html>